BLOOMINGTON, Ind. -- The asteroid presumed to have wiped out the dinosaurs struck the Earth with such force that carbon deep in the Earth's crust liquefied, rocketed skyward, and formed tiny airborne beads that blanketed the planet, say scientists from the U.S., U.K., Italy, and New Zealand in this month's Geology.
The beads, known to geologists as carbon cenospheres, cannot be formed through the combustion of plant matter, contradicting a hypothesis that the cenospheres are the charred remains of an Earth on fire. If confirmed, the discovery suggests environmental circumstances accompanying the 65-million-year-old extinction event were slightly less dramatic than previously thought.
"Carbon embedded in the rocks was vaporized by the impact, eventually forming new carbon structures in the atmosphere," said Indiana University Bloomington geologist Simon Brassell, study coauthor and former adviser to the paper's lead author, Mark Harvey.
The carbon cenospheres were deposited 65 million years ago next to a thin layer of the element iridium -- an element more likely to be found in Solar System asteroids than in the Earth's crust. The iridium-laden dust is believed to be the shattered remains of the 200-km-wide asteroid's impact. Like the iridium layer, the carbon cenospheres are apparently common. They've been found in Canada, Spain, Denmark and New Zealand.
But the cenospheres' origin presented a double mystery. The cenospheres had been known to geologists only as a sign of modern times -- they form during the intense combustion of coal and crude oil. Equally baffling, there were no power plants burning coal or crude oil 65 million years ago, and natural burial processes affecting organic matter from even older ages -- such as coals from the 300-million-year-old Carboniferous Period -- had simply not been cooked long or hot enough.
"Carbon cenospheres are a classic indicator of industrial activity," Harvey sa
'/>"/>
| Contact: David Bricker brickerd@indiana.edu 812-856-9035 Indiana University Source:Eurekalert |
Related biology news :
1. How your mothers emotional legacy impacts your life
2. Carnegie Mellon studies how climate change impacts food production
3. Lizard hunting styles impact ability to walk, run
4. Where college students live can impact their weight, eating and exercise habits
5. Yale study shows how rare genes have big impact on blood pressure
6. Researchers to develop ocean sanctuary noise budget to evaluate potential impact on marine mammals
7. Amphibians respond behaviorally to impact of clear cutting
8. Climate change has major impact on oceans
9. Adapting local ecosystems can soften impact of global climate change
10. Impacts of fossil fuels on fish and people
11. Bottom trawling impacts, clearly visible from space
 |
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |